In one form of conventional track structure, the track pin extending between the spaced parallel track links is received in a bushing having its opposite ends terminating in an aperture in an inner pair of track link portions. The ends of the pin extend outwardly from the bushing and are received in aligned apertures of an outer pair of track link portions. A number of seals have been developed for sealing the oil reservoir within the bushing. One improved form of such a seal comprises a C-shaped, or crescent seal, having one leg sealingly engaging the end of the bushing and the opposite leg sealingly engaging the outer track portion. A load ring is disposed between the legs so as to provide the desired sealing force of the legs against the sealing surfaces of the confronting track elements.
A problem has arisen in the manufacture of such seals in that it is necessary to provide a smooth sealing surface against which the seal leg is urged to assure the proper seal of the oil reservoir. It has been conventional to lap finish the metal surface so as to provide a surface roughness of approximately 4 to 6 microinches. The machine surfaces normally have a surface roughness of approximately 16 to 20 microinches and, thus, a substantial lapping operation is required.